There´s something called "UniWB", it is a white balance value that best represents the response of your sensor. To set it, just shoot an overexposed image so all 3 channels are cliped(lens out of focus, f/16, 3 seg exposure for example) and then use that image to set white balance. Now go to Custom Image, select "Natural" and lower the contrast to minimum.
Now the histogram is as truthful as possible (still some room on the right even if it shows clipped).

Now I re-read your post and I am not sure this is what you wanted. If you just want not to care about white balance, just use AWB... you can even fine tune it and save the WB so that it ermembers it after you turn off the camera.
The UniWB is useful if you shoot RAW and want to rely on the histogram.

I found it odd that the general belief for sunlight is 5500/5600k but the K5IIs daylight setting is 5000K.

I have a shoot with a girl tomorrow. I think I'm going to try setting the camera at 5600k with my speedlights and see what happens. I'll post some results as soon as I have a chance to go through them.

Yeah, I've noticed a big difference in the WB set on my K-5 compared to what LR shows. When I set my WB to 5600K to match my Einstein 640 strobes, which are supposed to have very consistent color, the color temps jump to 6100 in Light Room. It's not really a big deal in Light Room as you can just correct the WB on one photo and then copy/paste the settings to all of the other photos from that session. It did have me scratching my head when I first noticed the variation.

You could use a gray card or passport colorchecker if you really need to get close to the true color temp. Most of the time, I end up adjusting the WB anyway...
Shoot in RAW at 5600K and adjust to taste.

Take out a gray card and shoot the first image with the girl holding the card, in the typical lighting of your setup. If setup changes, repeat. You can calibrate camera WB to the gray card using the WB menues, or do it later in post processing (even if you shoot JPG, but RAW then would be highly recommended).

Then please, show her you know your stuff. Take out a gray card and shoot the first image with the girl holding the card, in the typical lighting of your setup. If setup changes, repeat. You can calibrate camera WB to the gray card using the WB menues, or do it later in post processing (even if you shoot JPG, but RAW then would be highly recommended). Gray cards are carried in every photo store.

I couldn't agree more, I also have a 18% grey lens cleaning cloth that is very useful for this purpose - these days there really isn't any excuse to be without a grey point reference.